From CTIGGM Geocal Issue 16: June 1997
Reviewed by R W Tomlinson & G Alexander, School of Geosciences, Queen's
University of Belfast, Belfast, BT7 1NN. Tel: 01232 335146; Fax: 01232
321280
An initial response to this CD-ROM might be to discount its value: because
of its American origin, it might be seen as irrelevant to a study of United
Kingdom topographic maps. However, such a response would be in error.
Certainly most of the instructions refer to American examples, in particular
to a 1:24,000 map of the Southwest Pueblo Quadrangle from the 7.5 Minute
Series (Topographic) of the USGS, but the principles of topographic mapping
are universal and on this CD-ROM are clearly and beautifully illustrated. |
Access to the material is easy and
the directions to various chapters could not be more straightforward.
The 'Introduction' is at a very simple level, but allows the reader
to delve into definitions simply by clicking onto the italicised
word. There follows a chapter on topographic maps in general which
includes a definition of 'True North' and 'Magnetic North' and how
the latter varies with time. The Transverse Mercator projection
is also introduced. The level of information given varies, but it
is not so simple that the average undergraduate could not profit
from going through this chapter. This is even more the case with
'Map Scale'. Here familiar items form the basis of the approach,
and good graphics and clearly explained terms ensure that the reader
should understand the concept of scale. Latitude and longitude are
defined equally well; the graphics, which show how angles are obtained
from the center of the earth, are especially noteworthy.
The chapter on 'Location and Public Land Survey' is less directly
relevant to general UK users, but for anyone with a particular interest
in cadastral survey of the USA it is a thorough and interesting
introduction. The Universal Transverse Mercator projection is fully
described in the next chapter, and this difficult subject is developed
with ease. The concepts of relief and altitude and the drawing of
contours are illustrated with 3-D models of drowning islands and
complete with sound effects -- which serve to remind one that it
is quite some time since the beginning of the CD-ROM and another
kind of relief is required! The construction of cross-sections with
suitable vertical exaggerations is also exemplified.
The last chapter deals with topographic maps, aerial photographs
and satellites, and is perhaps the weakest section, but it is only
an overview. Throughout the CD-ROM there are test-yourself questions
with a sonorous voice to tell you that your answer is 'CORRECT'
and a more discrete on-screen message to 'try again', -- and you
can cheat. At the end there is also a review to test your overall
knowledge.
Complete with a paper copy of the example map, and a raft of information
in the 'For Your Information' section of the disc, this is an excellent
production. It can be recommended for schools and for first-year
undergraduate study; students can fill gaps in their knowledge of
maps at their own speed and without recourse to traditional lectures
and practical classes.
-- R W Tomlinson & G Alexander
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From EARTH Magazine, April 1997,
p. 67
EARTH Magazine
Tasa Graphic Arts' Introduction to Topographic Maps delivers
just what the title promises. And even though the U.S. Geological
Survey provides a free brochure explaining topo maps, this CD-ROM
offers an easier path to understanding.
Following a review section, an "FYI" folder with background info
and a glossary of terms are 11 helpful chapters that discuss map
scale, contour lines, latitude and longitude, the Public Land Survey
system and remote sensing (aerial photos and satellite imagery).
The presentation lies at about the high school or college freshman
level.
Some people easily grasp the basic idea underlying map projection
-- distorting a sphere onto a flat sheet -- but not everyone can
envision it. For them it will be helpful to see a brief animation
that slices open a 3-D globe, unwraps it and flattens it into a
Mercator projection. Likewise, understanding magnetic declination
becomes simpler when the viewer can watch a compass needle change
direction relative to true north as the compass moves from east
to west.
Throughout the chapters, viewers encounter test-yourself questions
and exercises. This is good, but I wish the multiple choice answers
weren't quite so obvious. The real world offers few neat solutions.
University geology departments and high schools that offer advanced
classes will find this CD helpful, as will any earth science buff
wishing to understand topo maps.
-- Robert Burnham
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From GEOTIMES, December 1994, p.
28
GEOTIMES, www.geotimes.org
On the heels of their Plate Tectonics CD, TASA Graphic Arts Inc.
has released an excellent topographic map tutorial on CD-ROM. Sections
include coordinate systems (state-plane and UTM), map projections,
contours, features on standard U.S. Geological Survey maps and map
scale. Beautiful graphics, sound, and animation make this a joy
to use. (I only wish they had a slide set based on the graphics!)
The shaded 3-D surface that rotates into a profile will knock your
socks off! I particularly like the contour example where a hilly
surface is slowly flooded with water and contour lines are rendered
on a plane floating above the surface. -- Arthur B. Busbey
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